128 P. P. COWLES. 



Sections show that there is no circular muscle layer below the 

 epidermis and also that there is no muscular layer enveloping the 

 alimentary canal. Fraipont observed these facts also. 



Although the worms reared by the diatom method had not 

 reached sexual maturity, there can be no doubt but what the 

 form is P. appendiculatus, since the two characteristics which dis- 

 tinguish this species from all others are present, namely : 



The advanced stage of the development of the trunk before the 

 primary cuticle of the larva is broken and the presence of the two 

 filaments on the anal segment. 



There is another Polygordius larva which has been taken in the 

 tow at Beaufort, N. C., but its metamorphosis is different from 

 that of P. appendiculatus and the anal filaments are not present. 

 Although the writer has not attempted to rear the larva, its meta- 

 morphosis and anatomy resemble that of P. ncapolitamts. 



The Polygordii, raised by the diatom method, were found to be 

 very active little worms. By means of the glandular papillae on 

 the anal segments, they were usually found attached to the bottom 

 of the dish, but the rest of the body anterior to this was kept in 

 almost continual motion, waving back and forth and often tying 

 itself into knots. 



It is not strange if Polygordins has not been found on this 

 coast. In addition to the fact that they are small, thread-like 

 worms living free in the sand, they have the habit of coiling 

 themselves into a minute snake-like coil when disturbed. If they 

 are not more abundant than the most abundant annelids at Beau- 

 fort, it would only be by the most painstaking search that they 

 would be found. 



